Technical Field
This disclosure is directed to integrated circuits, and more particularly, to a reference circuit for a metrology system used monitoring parameters such as temperature and voltage during the operation of an integrated circuit.
Description of the Related Art
As features sizes have decreased, the number of transistors on integrated circuits (ICs) has correspondingly increased. The increased number of transistors per unit area has resulted in a corresponding increase in thermal output of ICs. Furthermore, the increased number of transistors per unit area has also corresponded to a decrease in the supply voltages provided to various functional circuitry on an IC. This has in turn led to significant challenges in balancing performance, power consumption, and thermal output of ICs. To this end, many ICs implement subsystems that monitor various metrics of the IC (e.g., temperature, voltage, voltage droops) and adjust the performance based on received measurements. For example, a control subsystem may reduce a clock frequency, supply voltage, or both, responsive to a temperature reading that exceeds a predefined threshold. This may help maintain operation of the IC within specified thermal limits. Such control systems may also boost the performance of certain functional circuits when measured metrics are well within limits.
IC subsystems used to control performance based on system metrics typically include one or more sensors and at least one control system. Due to factors such as process, voltage, and temperature variations, at least some of the sensors of such a subsystem may be coupled to receive power from a supply different from that used to power functional circuitry in the IC.